retrocycler

Ive got an older Fisher MTB with a Bontrager carbon crank. The bearings feel stiff, so while the bike is still in use, I want to shop bb options. Online (including this forum) I've not been able to find any details about what kind of BB is used with this crank.
The current BB is an "external" bearing type, and the cups have a marking "BCA 35-05" It looks like a 35mm spindle so that makes some sense. But there's no brand marking.
I assume english thread BB shell/threading.
Has anyone got any advice esperience with these?
Many thanks.
Boris

fietsbob

External Bearing BB types have the tubular spindle as part of the crank arm not separate,
so no choice, needed. or alternatives offered.

For Specifics Bontrager is a Trek brand name So Why not ask your Trek Dealer?

They own the Fisher brand too.. Now.






...

Mitch@Trek

Hey there, what year and model is the bike that you have? I can check our archives to see what the OE spec was listed at.

retrocycler

Hi Mitch, thanks for your reply! Following your suggestion, I've done more research. This forum link below shows the exact bike, apparently from 2007:

<URL that I'm not allowed to post here> (I'll try a PM) Appears to be a Procaliber Genesis

It's the exact same frame, mostly the same parts, particularly it is the same crank.

About the crank I now have an additional question. Last night I wanted to remove the crank but was stumped by the left crankarm (didn't get very far;-). The arm is pressed onto splines on the spindle (which is one piece with the right side arm/rings). My problem is that the threads in the left crank arm, that a puller tool would engage, are one inch in diameter. I've never seen that before, and now trying to find such a tool online, I've had no luck. Any tips on the correct tool, or correct search terms would be much appreciated.

thanks,

Boris

retrocycler

Ha, apparently I'm not allowed to PM Mitch@Trek either. Gee, how to communicate this:

expeditionportal
dot
com slash forum slash threads slash gary-fisher-procaliber-race-day-mountain-bike-17-5%E2%80%9D.41560/

retrocycler

or... to save yourself typing, if you google "gary fisher procaliber genesis," then the very first hit is that forum post describing the bike. The top tube says "Procaliber" and the stays say "Genesis geometry"
I hope that helps!
<image attachment that I'm not allowed!>
fair non-commercial use of this image

Mitch@Trek

So it looks like you'll need a threaded TruVativ GXP BB w/ English threads. To remove that crank, it appears to be a self-exctracting crank which relies on allen keys to be fitted into the non-drive side arm. There are some good YouTube videos to show how to remove these as they are quite easy!

retrocycler

MItch@Treck, many thanks!

My experience dating mainly from the 1970's and 1980's technology caused my expectations to be far more complicated than necessary! What I thought was a dust cap / thread protector was instead an integral part of the removal engineering - it was indeed very easy to remove the crank arm, after I read your reply. The bolt that holds the crank on the spindle is also the part that pulls the crank off, pushing against the "thread protector." Easy...

And now, with the cranks off, I see that the spindle is nothing like 35mm in diameter, it is a standard, typical diameter (about 23mm). The way the crank looks on the drive side, the way the "looks" are designed, makes it appear to be a huge diameter spindle. So now I'm off to shop for that BB, many thanks to all! (when I thought the spindle was 35mm diameter, none of the bottom brackets I saw referenced online looked like they would fit this spindle. Now that mystery is no more)

Boris out.